CN106328780B - The method of light emitting diode substrate epitaxial growth based on AlN templates - Google Patents

Abstract

The invention discloses a method for epitaxial growth of a light-emitting diode substrate based on an AlN template, comprising: processing a substrate, growing an Al _x Ga _(1-x) N layer, growing an Al _y Ga _(1-y) N layer, and growing a Si _v Al _z Ga _(1‑z‑v) N layer, grow Si-doped N-type GaN layer, grow In _x1 Ga _(1‑x1) N/GaN light emitting layer, where x1=0.20‑0.25, grow P-type AlGaN layer 1. Growing a P-type GaN layer doped with magnesium, and cooling down. The invention simplifies the epitaxial growth and improves the production efficiency of the LED.

Description

Method of Epitaxial Growth of Light Emitting Diode Substrate Based on AlN Template

technical field

The present invention relates to the technical field of epitaxial growth of a light emitting diode substrate, and more specifically relates to a method for epitaxial growth of a light emitting diode substrate based on an AlN template.

Background technique

Light Emitting Diode (LED for short) is a kind of semiconductor diode and a device that can convert electrical energy into light energy. LED products have the advantages of energy saving, environmental protection, long life and so on, and are widely loved by people. At present, the LED market is pursuing high-brightness LED products. The traditional LED structure mainly includes: substrate substrate, low-temperature buffer layer GaN, GaN layer not doped with Si, GaN layer doped with Si, light-emitting layer, doped Mg, GaN layer of Al, GaN doped with Mg at high temperature, Indium Tin Oxide (ITO for short) layer, SiO ₂ protection layer, P electrode and N electrode.

In the existing LED epitaxial generation process, the sapphire PSS substrate is used to grow the epitaxial layer. However, the growth of the epitaxial layer on the PSS substrate will cause a large density of defects in the epitaxial layer, resulting in low wavelength hit rate of the prepared epitaxial wafer, light crystal quality of the epitaxial wafer, poor crystal quality of the light-emitting layer, and low doping efficiency of the P layer. , the mobility of the holes is reduced; leading to problems such as a decrease in brightness, a decrease in luminous efficacy, a decrease in reverse voltage, and poor antistatic ability in the prepared LED.

As shown in Figure 1 and Figure 2, Figure 1 is a schematic flow chart of a traditional LED substrate epitaxial growth method in the prior art; Figure 2 is a structural schematic diagram of a traditional LED obtained by using the light-emitting diode substrate epitaxial growth method in the prior art . Among them, the traditional LED substrate epitaxial growth method includes the following steps:

Step 101, processing the sapphire substrate: in a hydrogen atmosphere at 1000-1100°C, feed 100L/min-130L/min of H ₂ , keep the reaction chamber pressure at 100-300mbar (mbar is the air pressure unit), and process the sapphire substrate 5-10 minutes.

Step 102, grow low-temperature buffer layer GaN: lower the temperature to 500-600°C, keep the pressure in the reaction chamber at 300-600mbar, and feed NH ₃ at a flow rate of 10000-20000sccm (sccm is standard ml per minute), TMGa at 50-100sccm, 100L /min-130L/min of H ₂ , and grow a low-temperature buffer layer GaN with a thickness of 20-40nm on the sapphire substrate.

Step 103, corroding the low-temperature buffer layer GaN into an irregular island shape: raise the temperature to 1000-1100°C, keep the reaction chamber pressure at 300-600mbar, and feed NH ₃ at a flow rate of 30000-40000sccm, 100L/min-130L/ Min of H ₂ , keep the temperature stable and continue at low temperature for 300-500s to etch GaN into irregular islands.

Step 104, growing an undoped U-shaped GaN layer: raise the temperature to 1000-1200°C, keep the reaction chamber pressure at 300-600mbar, and feed in NH ₃ , 200 -400sccm of TMGa, 100-130L/min of H ₂ , continuous growth of 2-4μm undoped GaN.

Step 105, grow the first Si-doped N-type GaN layer: keep the pressure and temperature of the reaction chamber constant, and feed NH ₃ with a flow rate of 30000-60000 sccm (sccm remark standard milliliters per minute), 200-400 sccm of TMGa, 100 -130L/min of H ₂ , 20-50sccm of SiH ₄ to continuously grow the first Si-doped N-type GaN layer of 3-4μm, Si doping concentration 5E18-1E19atom/cm ³ (Note 1E19 represents 10 to the 19th power That is 10 ^∧ 19, and so on).

Step 106, grow the second Si-doped N-type GaN layer: keep the pressure and temperature of the reaction chamber constant, and feed NH ₃ with a flow rate of 30000-60000 sccm (sccm remark standard ml per minute), TMGa of 200-400 sccm, 100 - 130 L/min of H ₂ and 2-10 sccm of SiH ₄ continuously grow the second Si-doped N-type GaN of 200-400 nm, and the Si doping concentration is 5E17-1E18 atom/cm ³ .

Step 107, grow the N-type GaN layer doped with Si in the luminescent layer: keep the pressure of the reaction chamber at 300-400mbar, the temperature at 750-850°C, and feed in NH ₃ , 20- 40sccm TMGa, 100-130L/min N ₂ , 2-10sccm SiH ₄ continuously grow 50-100nm Si-doped N-type GaN layer, Si doping concentration 1E18-5E18 atom/cm ³ .

Step 108, growing the In _x Ga _(1-x) N/GaN layer in the light-emitting layer: keep the pressure of the reaction chamber at 300-400mbar, the temperature at 700-750°C, and feed in NH ₃ at a flow rate of 50000-70000sccm, 20-40sccm TMGa, TMIn of 1500-2000sccm, N ₂ of 100-130L/min, grow In-doped 2.5-3.5nmIn _x Ga _(1-x) N (x=0.20-0.25), luminescence wavelength 450-455nm; The high temperature is 750-850°C, and the reaction chamber pressure is kept at 300-400mbar. The flow rate is 50,000-70,000sccm of NH ₃ , 20-100sccm of TMGa, and 100-130L/min of N ₂ , and grow 8-15nm GaN layer; then repeat In _x The growth of Ga _(1-x) N, and then repeat the growth of GaN, and alternately grow In _x Ga _(1-x) N/GaN light-emitting layers, and control the number of cycles to 7-15.

Step 109, growing a P-type AlGaN layer: keep the reaction chamber pressure at 200-400mbar, temperature at 900-950°C, feed NH ₃ at a flow rate of 50000-70000sccm, TMGa at 30-60sccm, _H2 at 100-130L/min, 100 - 130sccm of TMAl, 1000-1300sccm of Cp ₂ Mg, continuous growth of 50-100nm P-type AlGaN layer, Al doping concentration 1E20-3E20atom/cm ³ , Mg doping concentration 1E19-1E20atom/cm ³ .

Step 110, growing a magnesium-doped P-type GaN layer: keep the pressure of the reaction chamber at 400-900 mbar, the temperature at 950-1000° C., and feed in NH ₃ at a flow rate of 50,000-70,000 sccm, TMGa at 20-100 sccm, and H at 100-130 L/min _2. Cp ₂ Mg of 1000-3000 sccm, continuously growing a P-type GaN layer doped with magnesium with a thickness of 50-200 nm, and Mg doping concentration of 1E19-1E20 atom/cm ³ .

Step 111, lowering the temperature and cooling: finally lowering the temperature to 650-680°C, keeping it warm for 20-30 minutes, then turning off the heating system and the gas supply system, and cooling with the furnace.

As shown in FIG. 2 , conventional LEDs are prepared by using the epitaxial growth method of light-emitting diode substrates in the prior art, including the following structure from bottom to top: substrate 201, a low-temperature buffer layer GaN layer 202, a U-shaped GaN layer 203, N Type GaN layer 204, N electrode 205, light emitting layer 206 (including GaN layer 261 and In _x Ga _(1-x) N layer 262), P-type AlGaN layer 207 doped with Mg and Al, P-type AlGaN layer doped with Mg at high temperature GaN layer 208 , ITO layer 209 , SiO ₂ protective layer 210 and P electrode 211 .

Therefore, it is an urgent problem to be solved in this field to provide an epitaxial growth method of LED substrates with high wavelength hit rate, good light efficiency, high brightness, low voltage, high reverse voltage and strong antistatic ability of epitaxial wafers.

Contents of the invention

In view of this, the present invention provides a method for epitaxial growth of a light-emitting diode substrate based on an AlN template, which solves the problems of low wavelength hit rate, poor light efficiency, low brightness, high voltage, and reverse Technical problems of low voltage and poor antistatic ability.

In order to solve the above technical problems, the present invention proposes a method for epitaxial growth of a light-emitting diode substrate based on an AlN template, including: processing the substrate, growing an Al _x Ga _(1-x) N layer, growing an Al _y Ga _{(1-y )} N layer, grow Si _v Al _z Ga _(1-zv) N layer, grow Si-doped N-type GaN layer, grow In _x1 Ga _(1-x1) N/GaN light-emitting layer, where x1=0.20-0.25 , growing a P-type AlGaN layer, growing a P-type GaN layer doped with magnesium, and cooling down; wherein,

Growth Al _x Ga _(1-x) N layer, further:

Keep the pressure of the reaction chamber at 100-300mbar, the temperature at 900-1000°C, and at the same time feed the conditions of 30000-40000sccm of _NH3 , 100-130L/min of _N2 , 50-100sccm of TMGa and 100-200sccm of TMAl Next, grow a 500-800nm Al _x Ga _(1-x) N layer (x range: 0.10-0.15);

Growth Al _y Ga _(1-y) N layer, further:

Keep the pressure of the reaction chamber at 100-300mbar, the temperature at 1000-1200°C, and at the same time feed the conditions of 30000-50000sccm of _NH3 , 100-130L/min of _N2 , 100-200sccm of TMGa and 50-100sccm of TMAl Next, grow a 500-800nm Al _y Ga _(1-y) N layer (y range: 0.05-0.10);

Growth Si _v Al _z Ga _(1-zv) N layer, further:

Keep the pressure of the reaction chamber at 300-600mbar, the temperature at 1000-1200°C, and at the same time feed the flow rate of 30000-60000sccm _NH3 , 100-130L/min of _H2 , 200-300sccm of TMGa, 50-100sccm of TMAl and 5 Under the condition of -10sccm SiH ₄ , grow 500-800nm Si _v Al _z Ga _(1-zv) N layer (z range: 0.03-0.05; v range: 0.005-0.01), Si The doping concentration is 5E17-5E18 atom/cm ³ .

Further, wherein the processing substrate is further:

Into the reaction chamber of the metal-organic chemical vapor deposition system where the substrate is placed, simultaneously feed NH ₃ with a flow rate of 10000-20000 sccm and H ₂ at 100-130 L/min, raise the temperature to 900-1000 ° C, and in the reaction chamber The substrate is processed at a pressure of 100-200 mbar.

Further, wherein, growing the Si-doped N-type GaN layer is further: passing through NH3, TMGa, _H2 and _SiH4 to continuously grow the Si-doped N-type GaN layer.

Further, wherein the N-type GaN layer doped with Si is grown, further:

Keep the pressure of the reaction chamber at 300-600mbar, the temperature at 1000-1200°C, and the flow rate of NH3 at 30000-60000sccm, TMGa at 200-400sccm, _H2 at 100-130L/min, and SiH4 at _20-50sccm for continuous growth3 - 4 μm Si-doped N-type GaN layer, wherein the Si doping concentration is 5E18-1E19 atom/cm ³ .

Further, wherein the N-type GaN layer doped with Si is grown, further:

Keep the pressure of the reaction chamber at 300-600mbar, the temperature at 1000-1200°C, and the flow rate of NH3 at 30000-60000sccm, TMGa at 200-400sccm, _H2 at 100-130L/min, and SiH4 at _20-50sccm for continuous growth3 - a first Si-doped N-type GaN layer of 4 μm, wherein the Si doping concentration is 5E18-1E19 atom/cm ³ ;

Keep the pressure of the reaction chamber at 300-600mbar, the temperature at 1000-1200°C, and the flow rate of NH ₃ at 30000-60000sccm, TMGa at 200-400sccm, _H2 at 100-130L/min, and SiH4 at _2-10sccm for continuous growth A second Si-doped N-type GaN layer of 200-400 nm, wherein the Si doping concentration is 5E17-1E18 atom/cm ³ .

Further, wherein the N-type GaN layer doped with Si is grown, further:

Keep the pressure of the reaction chamber at 300-600mbar, the temperature at 1000-1200°C, and the flow rate of NH3 at 30000-60000sccm, TMGa at 200-400sccm, _H2 at 100-130L/min, and SiH4 at _20-50sccm for continuous growth3 - a first Si-doped N-type GaN layer of 4 μm, wherein the Si doping concentration is 5E18-1E19 atom/cm ³ ;

Keep the pressure of the reaction chamber at 300-600mbar, the temperature at 1000-1200°C, and the flow rate of NH ₃ at 30000-60000sccm, TMGa at 200-400sccm, _H2 at 100-130L/min, and SiH4 at _2-10sccm for continuous growth A second Si-doped N-type GaN layer of 200-400 nm, wherein the Si doping concentration is 5E17-1E18 atom/cm ³ ;

Keep the pressure of the reaction chamber at 300-400mbar, the temperature at 750-850°C, and the flow rate of NH ₃ at 30000-60000sccm, TMGa at 20-40sccm, _N2 at 100-130L/min, and SiH4 at _2-10sccm for continuous growth A third Si-doped N-type GaN layer with a thickness of 50-100 nm, and a Si doping concentration of 1E18-5E18 atom/cm ³ .

Further, wherein the In _x1 Ga _(1-x1) N/GaN light-emitting layer is grown, further:

Keep the pressure of the reaction chamber at 300-400mbar, the temperature at 700-750°C, and the flow rate of NH ₃ at 50000-70000sccm, TMGa at 20-40sccm, TMIn at 1500-2000sccm and _N2 at 100-130L/min , growing an In _x1 Ga _(1-x1) N layer doped with In at 2.5-3.5nm, wherein, x1=0.20-0.25, and the emission wavelength is 450-455nm;

Raise the temperature to 750-850°C, keep the pressure of the reaction chamber at 300-400mbar, and feed 50000-70000sccm of _NH3 , 20-100sccm of TMGa and 100-130L/min of _N2 to grow 8- 15nm light-emitting GaN layer; repeated alternate growth of In _x1 Ga _(1-x1) N layer and light-emitting GaN layer to obtain In _x1 Ga _(1-x1) N/GaN light-emitting layer, where In _x1 Ga _(1-x1) N The number of alternating growth cycles of the GaN layer and the light-emitting GaN layer is 7-15.

Further, wherein, growing the P-type AlGaN layer is further:

Keep the pressure of the reaction chamber at 200-400mbar, the temperature at 900-950°C, and the flow rate of NH ₃ at 50000-70000sccm, TMGa at 30-60sccm, _H2 at 100-130L/min, TMAl at 100-130sccm, 1000- 1300sccm of Cp ₂ Mg, continuously growing a 50-100nm P-type AlGaN layer, wherein the Al doping concentration is 1E20-3E20atom/cm ³ , and the Mg doping concentration is 1E19-1E20atom/cm ³ .

Further, wherein, growing a p-type GaN layer doped with magnesium is further:

Keep the pressure of the reaction chamber at 400-900mbar, the temperature at 950-1000°C, and feed the flow of NH ₃ at 50000-70000sccm, TMGa at 20-100sccm, _H2 at 100-130L/min, and _Cp2Mg at 1000-3000sccm, A magnesium-doped P-type GaN layer is continuously grown with a thickness of 50-200 nm, wherein the Mg doping concentration is 1E19-1E20 atom/cm ³ .

Further, wherein, cooling down is further:

After cooling down to 650-680°C, keep it warm for 20-30 minutes, turn off the heating system and the gas supply system, and cool down with the furnace to obtain a light-emitting diode based on an AlN template.

Compared with the prior art, the AlN template-based method for the epitaxial growth of a light-emitting diode substrate of the present invention achieves the following beneficial effects:

(1) The method for epitaxial growth of light-emitting diode substrates based on AlN templates in the present invention uses sputtering principles to sputter AlN templates on the substrate of LEDs, and utilizes AlN templates to replace the low-temperature GaN layer of traditional LEDs. The growth of high-temperature NGaN on the AlN template does not require the low-temperature GaN layer of traditional LEDs and the low-temperature GaN layer is etched into an island shape, which simplifies epitaxial growth and improves the production efficiency of LEDs.

(2) The method for the epitaxial growth of light-emitting diode substrates based on AlN templates of the present invention grows AlGaN layers and nAlGaN layers on AlN templates, which solves the transition from AlN templates to N-type GaN layers well, and solves the problem of The growth process of directly growing GaN on the AlN template is complicated, and the U-type GaN and N-type GaN obtained by the growth are extremely warped.

(3) The method for the epitaxial growth of light-emitting diode substrates based on the AlN template of the present invention improves the wavelength hit rate of the epitaxial wafers in the LED, improves the crystal quality of the epitaxial wafers, improves the crystal quality of the light-emitting layer, and improves the crystal quality of the P-type GaN layer. The improvement of doping efficiency, hole mobility, and wavelength hit rate increase the brightness and light efficiency of the LED, and the hole mobility of the P-type GaN layer increases, causing the voltage to drop; the improvement of crystal quality increases the reverse voltage , The antistatic ability is improved, and the luminous efficiency of the LED is improved as a whole.

Of course, any product implementing the present invention does not necessarily need to achieve all the above-mentioned technical effects at the same time.

Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

FIG. 1 is a schematic flow chart of a traditional LED substrate epitaxial growth method in the prior art;

Fig. 2 is the structural schematic view of traditional LED obtained by the preparation of light-emitting diode substrate epitaxial growth method in the prior art;

3 is a schematic flow diagram of the method for epitaxial growth of a light-emitting diode substrate based on an AlN template according to Embodiment 1 of the present invention;

Fig. 4 is a schematic structural diagram of an LED prepared by using the method for epitaxial growth of a light-emitting diode substrate based on an AlN template described in Embodiment 1 of the present invention;

FIG. 5 is a schematic flowchart of the method for epitaxial growth of a light-emitting diode substrate based on an AlN template according to Embodiment 2 of the present invention.

Detailed ways

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangements of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and in no way taken as limiting the invention, its application or uses.

Techniques, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques, methods and devices should be considered part of the description.

In all examples shown and discussed herein, any specific values should be construed as exemplary only, and not as limitations. Therefore, other instances of the exemplary embodiment may have different values.

It should be noted that like numbers and letters denote similar items in the following figures, therefore, once an item is defined in one figure, it does not require further discussion in subsequent figures.

Example 1

As shown in Figure 3, it is a schematic flow chart of the method for epitaxial growth of light-emitting diode substrates based on AlN templates described in this embodiment. The method described in this embodiment solves the problem of the method for preparing LEDs in the prior art. The wavelength hit rate is low, the crystal quality of the epitaxial wafer is light, the crystal quality of the light-emitting layer is poor, the doping efficiency of the P layer is reduced, and the mobility of the holes is reduced; resulting in a decrease in brightness, a decrease in luminous efficacy, and a decrease in reverse voltage. Poor antistatic ability and other problems.

In this embodiment, MOCVD (metal organic compound chemical vapor deposition) is used to grow high-brightness GaN-based LED epitaxial wafers, using high-purity _H2 or high-purity _N2 or a mixed gas of high-purity _H2 and high-purity _N2 As carrier gas, high-purity _NH3 as N source, metal-organic source trimethylgallium (TMGa), triethylgallium (TEGa) as gallium source, trimethylindium (TMIn) as indium source, N-type dopant Silane (SiH ₄ ), trimethylaluminum (TMAl) as the aluminum source, P-type dopant is magnesocene (CP ₂ Mg), the substrate is sapphire substrate, and the reaction pressure is between 70mbar and 900mbar, specifically including Follow the steps below:

Step 301, processing the sapphire substrate.

Step 302, growing an _{AlxGa (1-x)} N layer, further:

Keep the pressure of the reaction chamber at 100-300mbar, the temperature at 900-1000°C, and at the same time feed the conditions of 30000-40000sccm of _NH3 , 100-130L/min of _N2 , 50-100sccm of TMGa and 100-200sccm of TMAl Next, grow a 500-800nm _{AlxGa (1-x)} N layer (x range: 0.10-0.15).

Step 303, growing an Al _y Ga _(1-y) N layer, further:

Keep the pressure of the reaction chamber at 100-300mbar, the temperature at 1000-1200°C, and at the same time feed the conditions of 30000-50000sccm of _NH3 , 100-130L/min of _N2 , 100-200sccm of TMGa and 50-100sccm of TMAl Next, grow a 500-800nm _{AlyGa (1-y)} N layer (y range: 0.05-0.10).

Step 304, growing a Si _v Al _z Ga _(1-zv) N layer, further:

Keep the pressure of the reaction chamber at 300-600mbar, the temperature at 1000-1200°C, and at the same time feed the flow rate of 30000-60000sccm _NH3 , 100-130L/min of _H2 , 200-300sccm of TMGa, 50-100sccm of TMAl and 5 Under the condition of -10sccm SiH ₄ , grow a 500-800nm Si _v Al _z Ga _(1-zv) N layer (z range: 0.03-0.05; v range: 0.005-0.01), Si The doping concentration is 5E17-5E18 atom/cm ³ .

Step 305 , growing a Si-doped N-type GaN layer.

Step 306, growing an In _x1 Ga _(1-x1) N/GaN light-emitting layer, where x1=0.20-0.25.

Step 307 , growing a P-type AlGaN layer.

Step 308 , growing a p-type GaN layer doped with magnesium.

Step 309 , cooling down.

In the LED manufacturing process, the growth process of directly growing the GaN layer on the AlN layer is very complicated, and the warpage between the grown U-type GaN layer and the N-type GaN layer is also very large, which requires very strict control to grow. The GaN layer with relatively good quality can be produced, and the wavelength hit rate is low, which makes it impossible to realize mass production. In this embodiment, AlGaN layer and nAlGaN layer are grown on the AlN template, which can avoid these problems well, and adjust the growth process parameters Reach a very wide range, improve the wavelength hit rate of the epitaxial wafer, improve the crystal quality of the epitaxial wafer, and thus improve the preparation process of the LED.

As shown in FIG. 4 , it is a schematic structural diagram of an LED prepared by using the method for epitaxial growth of a light-emitting diode substrate based on an AlN template described in this embodiment. The LED includes the following structure: a substrate 401, an Al _x Ga _(1-x) N layer 402, A _ly Ga _(1-y) N layer 403, Si _v Al _z Ga _(1-zv) N layer 404, Si-doped N-type GaN layer 405, In _x1 Ga _(1-x1) N/ GaN light emitting layer 406 , P-type AlGaN layer 407 , Mg-doped P-type GaN layer 408 , ITO layer 409 , SiO ₂ protection layer 410 , N electrode 411 and P electrode 412 .

Example 2

As shown in Figures 3-5, Figure 5 is a schematic flow chart of the method for epitaxial growth of light-emitting diode substrates based on AlN templates described in this embodiment. The specific content of the layer. The method for the epitaxial growth of a light-emitting diode substrate based on an AlN template described in this embodiment includes the following steps:

Step 501, processing the sapphire substrate: Into the reaction chamber of the metal-organic chemical vapor deposition system with the substrate placed, NH ₃ with a flow rate of 10000-20000 sccm and H ₂ with a flow rate of 100-130 L/min are introduced at the same time, and the temperature is raised to The substrate is processed for 300s-600s at 900-1000° C. under the condition that the reaction chamber pressure is 100-200 mbar.

Step 502, growing an _{AlxGa (1-x)} N layer, further:

Keep the pressure of the reaction chamber at 100-300mbar, the temperature at 900-1000°C, and at the same time feed the conditions of 30000-40000sccm of _NH3 , 100-130L/min of _N2 , 50-100sccm of TMGa and 100-200sccm of TMAl Next, grow a 500-800nm _{AlxGa (1-x)} N layer (x range: 0.10-0.15).

Step 503, growing an Al _y Ga _(1-y) N layer, further:

Keep the pressure of the reaction chamber at 100-300mbar, the temperature at 1000-1200°C, and at the same time feed the conditions of 30000-50000sccm of _NH3 , 100-130L/min of _N2 , 100-200sccm of TMGa and 50-100sccm of TMAl Next, grow a 500-800nm _{AlyGa (1-y)} N layer (y range: 0.05-0.10).

Step 504, growing a Si _v Al _z Ga _(1-zv) N layer, further:

Keep the pressure of the reaction chamber at 300-600mbar, the temperature at 1000-1200°C, and at the same time feed the flow rate of 30000-60000sccm _NH3 , 100-130L/min of _H2 , 200-300sccm of TMGa, 50-100sccm of TMAl and 5 Under the condition of -10sccm SiH ₄ , grow 500-800nm Si _v Al _z Ga _(1-zv) N layer (z range: 0.03-0.05; v range: 0.005-0.01), Si The doping concentration is 5E17-5E18 atom/cm ³ .

Step 505, keep the reaction chamber pressure at 300-600mbar, temperature at 1000-1200°C, and feed in NH3 at 30000-60000sccm, TMGa at 200-400sccm, _H2 at 100-130L/min, and _SiH4 at 20-50sccm A first Si-doped N-type GaN layer of 3-4 μm is continuously grown, wherein the Si doping concentration is 5E18-1E19 atom/cm ³ .

Step 506, keep the reaction chamber pressure at 300-600mbar, temperature at 1000-1200°C, and feed in NH ₃ at 30,000-60,000 sccm, TMGa at 200-400 sccm, H ₂ at 100-130 L/min, and SiH at 2-10 sccm _4. Continuously grow a second Si-doped N-type GaN layer of 200-400 nm, wherein the Si doping concentration is 5E17-1E18 atom/cm ³ .

Step 507, keep the pressure of the reaction chamber at 300-400mbar, the temperature at 750-850°C, and feed in NH ₃ at 30,000-60,000 sccm, TMGa at 20-40 sccm, N ₂ at 100-130 L/min, and SiH at 2-10 sccm _4. Continuously grow a third Si-doped N-type GaN layer with a thickness of 50-100 nm, and the Si doping concentration is 1E18-5E18 atom/cm ³ .

Step 508, growing an In _x1 Ga _(1-x1) N/GaN light-emitting layer, where x1=0.20-0.25. The specific steps include: keeping the pressure of the reaction chamber at 300-400mbar, the temperature at 700-750°C, feeding in NH ₃ at a flow rate of 50000-70000sccm, TMGa at 20-40sccm, TMIn at 1500-2000sccm and N at 100-130L/min Under the condition of ₂ , grow 2.5-3.5nm In _x1 Ga _(1-x1) N layer doped with In, where x1=0.20-0.25, and the emission wavelength is 450-455nm;

Raise the temperature to 750-850°C, keep the pressure of the reaction chamber at 300-400mbar, and feed 50000-70000sccm of _NH3 , 20-100sccm of TMGa and 100-130L/min of _N2 to grow 8- 15nm light-emitting GaN layer; repeated alternate growth of In _x1 Ga _(1-x1) N/GaN layer and light-emitting GaN layer to obtain In _x1 Ga _(1-x1) N/GaN/GaN light-emitting layer, in which In _x1 Ga _{(1 -x1)} The number of alternating growth cycles of the N/GaN layer and the light-emitting GaN layer is 7-15.

Step 509, growing a P-type AlGaN layer: keep the pressure of the reaction chamber at 200-400 mbar, the temperature at 900-950° C., and feed in NH ₃ at a flow rate of 50,000-70,000 sccm, TMGa at 30-60 sccm, and H ₂ at 100-130 L/min , 100-130sccm of TMAl, 1000-1300sccm of Cp ₂ Mg, and continuously grow a 50-100nm P-type AlGaN layer, wherein, the Al doping concentration is 1E20-3E20atom/cm ³ , and the Mg doping concentration is 1E19-1E20atom/cm ³ .

Step 510, growing a P-type GaN layer doped with magnesium: keep the pressure of the reaction chamber at 400-900mbar, the temperature at 950-1000°C, and the flow rate of NH ₃ at 50000-70000sccm, TMGa at 20-100sccm, and 100-130L/min _1000-3000 sccm of Cp ₂ Mg to continuously grow a 50-200 nm magnesium-doped P-type GaN layer, wherein the Mg doping concentration is 1E19-1E20 atom/cm ³ .

Step 511 , cooling down: after cooling down to 650-680° C., keep warm for 20-30 minutes, turn off the heating system, turn off the gas supply system, and cool down with the furnace to obtain a light-emitting diode based on an AlN template.

The method for the epitaxial growth of a light-emitting diode substrate based on an AlN template described in this embodiment, grows an AlGaN layer and an nAlGaN layer on an AlN template, and solves the transition from an AlN template to an N-type GaN layer, and solves the problem in the AlN The growth process of directly growing GaN on the template is complicated, and the U-type GaN and N-type GaN obtained by the growth are extremely warped.

Example 3

In this embodiment, LED sample 1 was prepared according to the traditional LED growth method, and sample 2 was prepared according to the LED growth method of the present invention; parameters of the epitaxial growth methods of sample 1 and sample 2 are shown in Table 1. Put sample 1 and sample 2 into XRD measuring equipment (X-ray Diffraction, also known as X-ray diffractometer) at the same time to measure the value of GaN layer and the value of luminescence layer, see Table 3 for details. Then sample 1 and sample 2 are plated with about 150nm thick ITO layer under the same pre-process conditions; about 1500nm of Cr/Pt/Au electrodes are plated under the same conditions; The protective layer of SiO ₂ , and then the sample was ground and cut into chip particles of 635μm*635μm (25mil*25mil) under the same conditions, and then 100 crystal grains were selected from sample 1 and sample 2 at the same position. Packaged into a white LED under the packaging process. The photoelectric properties of sample 1 and sample 2 were tested with an integrating sphere under the condition of a driving current of 350mA, and the results are shown in Table 2.

Table 1, comparison table of growth parameters of sample 1 and sample 2

Table 2 Comparison results of electrical parameters of sample 1 and sample 2 products

Table 3 Determination results of XRD parameters of sample 1 and sample 2 epitaxial wafers

According to the data analysis of the above test results list, it can be seen that the data obtained by the integrating sphere are analyzed and compared, and the test data in Table 3 shows that the crystal quality of N-type GaN is improved by using the AlN template growth method, and the crystal quality of the light-emitting layer is improved, corresponding to Table 2. The LED luminous efficiency of the present invention is increased from 125m/w to 145Lm/w, the voltage drops by about 0.1V, and other parameters become better; it shows that the LED epitaxial growth method designed in the present invention can realize mass production of LEDs grown on AlN templates, and Get good LED products.

It can be seen from the above embodiments that the method for epitaxial growth of light-emitting diode substrates based on AlN templates of the present invention has the following beneficial effects:

(1) The method for epitaxial growth of light-emitting diode substrates based on AlN templates in the present invention uses sputtering principles to sputter AlN templates on the substrate of LEDs, and utilizes AlN templates to replace the low-temperature GaN layer of traditional LEDs. The growth of high-temperature NGaN on the AlN template does not require the low-temperature GaN layer of traditional LEDs and the low-temperature GaN layer is etched into an island shape, which simplifies epitaxial growth and improves the production efficiency of LEDs.

(2) The method for the epitaxial growth of light-emitting diode substrates based on AlN templates of the present invention grows AlGaN layers and nAlGaN layers on AlN templates, which solves the transition from AlN templates to N-type GaN layers well, and solves the problem of The growth process of directly growing GaN on the AlN template is complicated, and the U-type GaN and N-type GaN obtained by the growth are extremely warped.

(3) The method for the epitaxial growth of light-emitting diode substrates based on the AlN template of the present invention improves the wavelength hit rate of the epitaxial wafers in the LED, improves the crystal quality of the epitaxial wafers, improves the crystal quality of the light-emitting layer, and improves the crystal quality of the P-type GaN layer. The improvement of doping efficiency, hole mobility, and wavelength hit rate increase the brightness and light efficiency of the LED, and the hole mobility of the P-type GaN layer increases, causing the voltage to drop; the improvement of crystal quality increases the reverse voltage , The antistatic ability is improved, and the luminous efficiency of the LED is improved as a whole.

Those skilled in the art should understand that the embodiments of the present invention may be provided as methods, apparatuses, or computer program products. Accordingly, the present invention can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are for illustration only and not intended to limit the scope of the present invention. Those skilled in the art will appreciate that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims (9)

1. A method for epitaxial growth of a light-emitting diode substrate based on an AlN template, characterized in that, comprising: processing the substrate, growing Al _x Ga _(1-x) N layer, growing Al _y Ga _(1-y) N layer , grow Si _v Al _z Ga _(1-zv) N layer, grow Si-doped N-type GaN layer, grow In _x1 Ga _(1-x1) N/GaN light-emitting layer, wherein, x1=0.20-0.25, grow P Type AlGaN layer, growing P-type GaN layer doped with magnesium, and cooling down; wherein, Growth Al _x Ga _(1-x) N layer, further: Keep the pressure of the reaction chamber at 100-300mbar, the temperature at 900-1000°C, and at the same time feed the conditions of 30000-40000sccm of _NH3 , 100-130L/min of _N2 , 50-100sccm of TMGa and 100-200sccm of TMAl Next, grow a 500-800nm Al _x Ga _(1-x) N layer, and the value range of x is 0.10-0.15; Growth Al _y Ga _(1-y) N layer, further: Keep the pressure of the reaction chamber at 100-300mbar, the temperature at 1000-1200°C, and at the same time feed the conditions of NH ₃ at a flow rate of 30000-50000sccm, _N2 at 100-130L/min, TMGa at 100-200sccm and TMAl at 50-100sccm Next, grow a 500-800nm Al _y Ga _(1-y) N layer, and the value range of y is 0.05-0.10; Growth Si _v Al _z Ga _(1-zv) N layer, further: Keep the pressure of the reaction chamber at 300-600mbar, the temperature at 1000-1200°C, and at the same time feed in NH ₃ at a flow rate of 30000-60000sccm, H2 at 100-130L/min, TMGa at 200-300sccm, _TMAl at 50-100sccm and 5 Under the condition of -10sccm SiH ₄ , grow a 500-800nm Si _v Al _z Ga _(1-zv) N layer, the value range of z: 0.03-0.05, the value range of v: 0.005-0.01, the Si doped Impurity concentration 5E17-5E18atom/cm ³ ; Process the substrate, further as: Into the reaction chamber of the metal-organic chemical vapor deposition system where the substrate is placed, simultaneously feed NH ₃ with a flow rate of 10000-20000 sccm and H ₂ at 100-130 L/min, raise the temperature to 900-1000 ° C, and in the reaction chamber The substrate is processed at a pressure of 100-200 mbar. 2. The method for epitaxial growth of a light-emitting diode substrate based on an AlN template according to claim 1, characterized in that, growing an N-type GaN layer doped with Si, further comprising: feeding NH3, TMGa, _H2 and _SiH4 The Si-doped N-type GaN layer is continuously grown. 3. the method for the epitaxial growth of light-emitting diode substrate based on AlN template according to claim 2, is characterized in that, the N-type GaN layer of growth doping Si is further: Keep the pressure of the reaction chamber at 300-600mbar, the temperature at 1000-1200°C, and the flow rate of NH3 at 30000-60000sccm, TMGa at 200-400sccm, _H2 at 100-130L/min, and SiH4 at _20-50sccm for continuous growth3 - 4 μm Si-doped N-type GaN layer, wherein the Si doping concentration is 5E18-1E19 atom/cm ³ . 4. the method for the epitaxial growth of light-emitting diode substrate based on AlN template according to claim 3, is characterized in that, the N-type GaN layer of growth doping Si is further: Keep the pressure of the reaction chamber at 300-600mbar, the temperature at 1000-1200°C, and the flow rate of NH3 at 30000-60000sccm, TMGa at 200-400sccm, _H2 at 100-130L/min, and SiH4 at _20-50sccm for continuous growth3 - a first Si-doped N-type GaN layer of 4 μm, wherein the Si doping concentration is 5E18-1E19 atom/cm ³ ; Keep the pressure of the reaction chamber at 300-600mbar, the temperature at 1000-1200°C, and the flow rate of NH ₃ at 30000-60000sccm, TMGa at 200-400sccm, _H2 at 100-130L/min, and SiH4 at _2-10sccm for continuous growth A second Si-doped N-type GaN layer of 200-400 nm, wherein the Si doping concentration is 5E17-1E18 atom/cm ³ . 5. the method for the epitaxial growth of light-emitting diode substrate based on AlN template according to claim 4, is characterized in that, the N-type GaN layer of growth doping Si is further: Keep the pressure of the reaction chamber at 300-600mbar, the temperature at 1000-1200°C, and the flow rate of NH3 at 30000-60000sccm, TMGa at 200-400sccm, _H2 at 100-130L/min, and SiH4 at _20-50sccm for continuous growth3 - a first Si-doped N-type GaN layer of 4 μm, wherein the Si doping concentration is 5E18-1E19 atom/cm ³ ; Keep the pressure of the reaction chamber at 300-600mbar, the temperature at 1000-1200°C, and the flow rate of NH ₃ at 30000-60000sccm, TMGa at 200-400sccm, _H2 at 100-130L/min, and SiH4 at _2-10sccm for continuous growth A second Si-doped N-type GaN layer of 200-400 nm, wherein the Si doping concentration is 5E17-1E18 atom/cm ³ ; Keep the pressure of the reaction chamber at 300-400mbar, the temperature at 750-850°C, and feed the flow rate of 30000-60000sccm of NH ₃ , 20-40sccm of TMGa, 100-130L/min of N ₂ , and 2-10sccm of SiH ₄ for continuous growth A third Si-doped N-type GaN layer with a thickness of 50-100 nm, and a Si doping concentration of 1E18-5E18 atom/cm ³ . 6. the method for the epitaxial growth of light-emitting diode substrate based on AlN template according to claim 1, is characterized in that, grows In _x1 Ga _(1-x1) N/GaN light-emitting layer, further is: Keep the pressure of the reaction chamber at 300-400mbar, the temperature at 700-750°C, and the flow rate of _NH3 at 50000-70000sccm, TMGa at 20-40sccm, TMIn at 1500-2000sccm and _N2 at 100-130L/min , growing an In _x1 Ga _(1-x1) N layer doped with In at 2.5-3.5nm, wherein, x1=0.20-0.25, and the emission wavelength is 450-455nm; Raise the temperature to 750-850°C, keep the pressure of the reaction chamber at 300-400mbar, and feed 50000-70000sccm of _NH3 , 20-100sccm of TMGa and 100-130L/min of _N2 to grow 8- 15nm light-emitting GaN layer; repeated alternate growth of In _x1 Ga _(1-x1) N layer and light-emitting GaN layer to obtain In _x1 Ga _(1-x1) N/GaN light-emitting layer, where In _x1 Ga _(1-x1) N The number of alternating growth cycles of the GaN layer and the light-emitting GaN layer is 7-15. 7. the method for the epitaxial growth of light-emitting diode substrate based on AlN template according to claim 1, is characterized in that, grows P-type AlGaN layer, further is: Keep the pressure of the reaction chamber at 200-400mbar, the temperature at 900-950°C, and feed the flow rate of 50000-70000sccm of _NH3 , 30-60sccm of TMGa, 100-130L/min of _H2 , 100-130sccm of TMAl, 1000- 1300sccm Cp ₂ Mg, continuously growing a 50-100nm P-type AlGaN layer, wherein the Al doping concentration is 1E20-3E20atom/cm ³ , and the Mg doping concentration is 1E19-1E20atom/cm ³ . 8. the method for the epitaxial growth of light-emitting diode substrate based on AlN template according to claim 1, is characterized in that, grows the p-type GaN layer doped with magnesium, further is: Keep the pressure of the reaction chamber at 400-900mbar, the temperature at 950-1000°C, and feed the flow of NH ₃ at 50000-70000sccm, TMGa at 20-100sccm, _H2 at 100-130L/min, and _Cp2Mg at 1000-3000sccm, A magnesium-doped P-type GaN layer is continuously grown with a thickness of 50-200 nm, wherein the Mg doping concentration is 1E19-1E20 atom/cm ³ . 9. The method for epitaxial growth of a light-emitting diode substrate based on an AlN template according to claim 1, characterized in that, cooling down, further comprising: After cooling down to 650-680°C, keep it warm for 20-30 minutes, turn off the heating system and the gas supply system, and cool down with the furnace to obtain a light-emitting diode based on an AlN template.